Fire detecting device



April 30, 1963 w. w. WOOD 3,087,456

FIRE DETECTING DEVICE Filed Jan. 9, 1961 WW 4o FIG. 4

ll WI URN INVENTOR.

vv. DOB

10 6? warm TORNEY United States Patet Ofiice 3,087,456 FIRE DETECTING DEVICE Wilbu'rn W. Wood, 79 East Road, Tacoma, Wash. Filed Jan. 9, 1961, Ser. No. 81,328 3 Claims. (Cl. 116-105) This invention relates to improvements in fire detecting devices and more particularly is concerned with a fire detecting device incorporating integrally therein means for detecting and alerting occupants that a fire exists.

An important object of the present invention is to provide a fire detecting device which is inexpensive to manufacture and efficient and positive in operation, with the result that a home or other building may be equipped with a positive acting fire detecting system at very low cost.

Another object is to provide a fire detecting device which produces a novel warning signal to indicate that a fire or other overheated condition exists, and more particularly a signal in the form of an explosion-like noise which alerts occupants that such overheated condition exists.

A further object is to provide a fire detecting device which may be conveniently installed in a building without altering appreciably the structure of the building.

A further object is to provide a fire detecting device utilizing heat-controlled, gas generating means which when subjected to a selected temperature is adapted to pressurize a pressure chamber to a point of rupture to produce an audible report.

A still further object is to provide a combination fire detecting device and holder, with the latter member being adapted to position the detecting device in spaced relation from a wall surface whereby said device is influenced by heat from all sides and furthermore is not influenced by the temperature of the surface on which it is supported.

Briefly stated, the fire detecting device of the instant invention comprises a tubular body member formed of a heat conducting metal and having an intermediate diaphragm which divides the body member into a pressure chamber and a nozzle. The pressure chamber carries a pair of chemicals which when exposed to each other react to produce a gas to pressurize said chamber. One of the chemicals is confined within a fusible container adapted to melt at a predetermined temperature to permit the reaction with the other chemical element. The diaphragm is arranged to rupture at a certain pressure and allow instantaneous discharge of the gas in the pressure chamber to cause a loud and sharp audible report, thus indicating the presence of overheated conditions.

The invention will be better understood and other objects thereof will become apparent from the accompanying specification and claims considered together with the accompanying drawings, wherein like numerals of reference indicate like parts.

FIGURE 1 is a perspective view of the present fire detecting device with parts thereof broken away to show internal structure;

FIGURE 2 is an enlarged top plan view of the fusible container which carries one of the chemicals;

FIGURE 3 is a sectional view of the fusible container, taken on the line 33 of FIGURE 2;

FIGURE 4 is a front elevational view of the present device on a reduced scale in combination with a holder therefor; and

FIGURE 5 is a top plan view of the device shown in FIG. 4 and its holder.

Referring now particularly to the drawings, the pres ent fire detecting device, designated generally by the numeral 8, comprises a tubular body portion having a 3,087,456 Patented Apr. 30, 1963 closed end 12 and an open end 14. In the formation of the body portion 10 there is provided an annular groove 16 opening inwardly of said body portion. This groove receives a diaphragm 18 in a pressed or otherwise snug fit whereby such diaphragm forms one end of an air tight pressure chamber 20, the opposite end of chamber 20 comprising the closed end 12 of the body member.

Diaphragm 18 is formed -of a plate material which will withstand considerable pressure but which at a selected pressure will rupture instantaneously. The material from which the diaphragm is constructed may as an example, comprise a thin metal.

Body portion 10 preferably is formed of a heat conducting metal such as aluminum so that it will readily assume the temperature of surrounding temperature con ditions'. For this purpose, diaphragm 18 also is formed of a heat conducting metal.

Diaphragm .18 is provided with a weakened area prefera'bly adjacent its central portion so that when it ruptures as a result of pressure in the chamber 20 it will merely assume a punctured-like condition at its weakened area rather than in any case permitting fragments to break loose. For this purpose the diaphragm is provided with partially penetrating intersecting lines 22. It is to be understood that other forms of weakening lines or thinned areas may be provided to accomplish the desired results which are, first, to cause the diaphragm to fail prior to the other walls of the body member and, second, to rupture instantaneously to produce an audible report resulting from pressure discharge of the contents of the pressure chamber as will now be made more apparent.

Pressure in the chamber 20 is developed by the reaction of a pair of chemicals 24 and 2-6. That is, chemicals may be used which when exposed to each other react to form a gas such as, for example, bicarbonate of soda and acetic acid. Preferably one of the chemicals is incorporated freely within the chamber 20 and the other chemical is encased in a fusible container 28, and these elements may be utilized in preferred states such as liquid, cake, or powder. For purposes of illustration the chemical 24 is in liquid form and is contained freely within the chamber 20 and chemical 26 is in cake form and is encased in the container 23.

The metal of container 28 is adapted to melt at a selected temperature, for example a temperature of F., and upon melting will expose its contents to the other chemical, thus developing a gas which will pressurize the chamber 29 to a point wherein the diaphragm will rupture instantaneously to cause a sharp audible report. Chamber 20 may have, as illustrated, inwardly curved side wall portions 30 serving to reinforce such wall area against inner pressure.

By the arrangement illustrated, the chemicals 24 and 26 are prevented from contacting each other until such time as the container 28 melts. Thus, the detecting device may be packaged, installed, or otherwise handled without causing the chemicals accidentally to contact each other.

Also comprising a part of the present invention is a holder for the detecting device. In a preferred form this holder comprises a card or plate 32 having an aperture 34 at its top end for hanging on a nail 36 or the like. The detecting device is integrally attached to the car-d 32 by suitable means such as by straps or staples 38 with the open end 14 disposed downwardly.

As apparent in FIGURE 5, the card 32 is curved laterally, and by reason of such structure it supports the detecting device in spaced relation from the wall surface. Thus', the detecting device is exposed to heat on all sides for rapidly detecting and reporting overheated conditions.

The supporting card 32, by the structure shown, presents surfaces 40 capable of receiving printed matter 42 such as instructions or advertising.

In accordance with the present invention there is provided an extremely inexpensive fire detecting device which may be mounted at selected and preferred places in the home and which when subjected to a certain temperature will emit a sharp audible report. Such device may readily be supported on brads or the like, or merely laid on rafters, beams, or other portions of the building. The device is safe in operation and, when discharging, emits a harmless charge of non-toxic gas only. It is positioned by its supporting card in spaced relation from a supporting surface so as not to be influenced by the temperature of said surface.

It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. A fire detecing device comprising a hollow body member constructed of heat conducting material and having one closed end and one open end, a diaphragm mounted in an integral position adjacent the open end to seal said open end and form with said closed end of said body member a pressure chamber, a pair of chemicals in said pressure chamber adapted when exposed to each other to develop a gas charge for pressurizing said chamber, and fusible container means enclosing one of said chemicals and adapted to melt at a selected fire warning temperature and permit its chemical to be exposed to the other chemical for pressurizing said chamher, said diaphragm having a weakened area therein to cause one portion thereof to rupture first and prevent deterioration thereof and said weakened area being rupturable at a selected pressure for allowing instantaneous escape of said gas charge through said open end to produce an explosion-like alerting noise.

2. A fire detecing device comprising a hollow body member constructed of heat conducting material and having one closed end and one open end, a diaphragm mounted in an integral position adjacent the open end to seal said open end and form with said closed end of said body member a pressure chamber, a chemical in said pressure chamber adapted when heated to pressurize said chamber, said diaphragm having a weakened area therein to cause one portion thereof to rupture first and prevent deterioration thereof and said weakened area being rupturable at a selected pressure for allowing instantaneous escape of said gas charge through said open end to produce an explosion-like alerting noise.

3. The fire detecting device of claim 1 including a holder therefor, said holder being laterally arcuate and said device being supported on the outer curved surface thereof for spacing said body portion away from a supporting surface.

References Cited in the file of this patent UNITED STATES PATENTS 401,531 Agerskov Apr. 16, 1889 1,043,228 Harrington et a1. Nov. 5, 1912 2,138,149 Evans Nov. 29, 1938 2,483,657 Messick Oct. 4, 1949 

1. A FIRE DETECTING DEVICE COMPRISING A HOLLOW BODY MEMBER CONSTRUCTED OF HEAT CONDUCTING MATERIAL AND HAVING ONE CLOSED END AND ONE OPEN END, A DIAPHRAGM MOUNTED IN AN INTEGRAL POSITION ADJACENT THE OPEN END TO SEAL SAID OPEN END AND FORM WITH SAID CLOSED END OF SAID BODY MEMBER A PRESSURE CHAMBER, A PAIR OF CHEMICALS IN SAID PRESSURE CHAMBER ADAPTED WHEN EXPOSED TO EACH OTHER TO DEVELOP A GAS CHARGE FOR PRESSURIZING SAID CHAMBER, AND FUSIBLE CONTAINER MEANS ENCLOSING ONE OF SAID CHEMICALS AND ADAPTED TO MELT AT A SELECTED FIRE WARNING TEMPERATURE AND PERMIT ITS CHEMICAL TO BE EXPOSED TO THE OTHER CHEMICAL FOR PRESSURIZING SAID CHAMBER, SAID DIAPHRAGM HAVING A WEAKENED AREA THEREIN TO CAUSE ONE PORTION THEREOF TO RUPTURE FIRST AND PREVENT DETERIORATION THEREOF AND SAID WEAKENED AREA BEING RUPTURABLE AT A SELECTED PRESSURE FOR ALLOWING INSTANTANEOUS ESCAPE OF SAID GAS CHARGE THROUGH SAID OPEN END TO PRODUCE AN EXPLOSION-LIKE ALERTING NOISE. 